Yayoi Amatsuka is a veteran Valkyrie pilot deployed across Japan's critical combat zones. She previously served in the Self-Defense Forces before becoming a Valkyrie, participating in the first Valkyrie selection test alongside Misato Honjo and Akira Jinguji. Hailing from a wealthy family, she experienced a complex relationship with her relatives and struggled to reintegrate into civilian life, fostering a strong sense of independence. Standing 165 cm tall, Yayoi sports an eye-catching style featuring revealing outfits that expose her midriff and incorporate hot pants. Her personality blends a fierce, easygoing demeanor with a strong regional Japanese dialect. She adopts a protective "big sister" role towards younger Valkyries, particularly Sonoka Watarai, who addresses her as such. This protectiveness fuels her disapproval of deploying civilian recruits and children in combat. Her combat history includes holding the elite S-class designation "Helmwige" until a critical mission two years prior, the "Hundred-Ri Hellfront." During this operation, she deliberately sabotaged Sonoka Watarai’s aircraft to prevent her participation, driven by a premonition of disaster. The mission resulted in the death of comrade Akira Jinguji and Yayoi’s own aircraft being shot down. Though she survived, she lost her S-class rank and title, retaining A-class status. Yayoi demonstrates tactical expertise through her modified Grumman F7F Tigercat aircraft. This twin-engine fighter excels in dogfighting, ground attacks, and torpedo bombing but demands advanced handling skills. She equips it with rockets for specialized operations and commands a dedicated Shield Squadron that responds to her orders with naval-style acknowledgments. During the assault on the Fuji Primary Pillar, Yayoi volunteers for a perilous rescue mission after the initial operation fails. Before deploying, she reconciles with Sonoka Watarai, exchanging mementos: a rocket pendant from Sonoka and a protective charm from herself. She promises to return even if her aircraft is destroyed. Leading her Shield Squadron into combat, she successfully extracts the European Valkyrie Lizbet Crown but sustains critical damage. Her final act transmits a crucial message through Lizbet, revealing that Odin conceals critical information and identifying Claudia Bruford as pivotal to humanity’s survival. Yayoi and her squadron do not return. Her influence extends posthumously. The charm given to Sonoka contains a handwritten note encouraging perseverance during adversity. Her message about Odin’s deception and Claudia’s significance informs subsequent strategic decisions by Tateyama Base personnel. Her sacrifice and leadership legacy continue to resonate with active Valkyries and command staff.